Heat exchangers



Nov. 8, 1938.

C. F. ROSENBLAD HEAT EXCHANGER Filed Feb. 4, 1937 M z IYNVENTO M m'ronwsv Patented Nov. 8, 1938 PATENT OFFICE HEA'IKEXCHANGERS Curt Fredrik Rosenblad, Sodertal-J'e, Sweden, as-

signor toAktiebolaget Rosenblads l atenter, Sodertalje, Sweden, a corporation of. Sweden Application February 4, 1937, Serial No. 124,113

vIn Sweden February-1, 1936 4 Claims.

This invention refers to heat exchangers of the spiral sheet metal type, i. e. heat exchangers having the heat transmitting surfaces made of one or more metal sheets'wound to spirals, and 5 forming walls of the channels for the flowing media between which heatis to, be exchanged. The chief purpose of this invention is to render such apparatus more resistive to shocks and other stresses and strains, without increasing the quantity of material used and the weight of the apparatus. For the same resistance the heat exchanger in accordance with this invention may be constructed with a smaller quantity of material and have a lesser weight than that of ordi- 17, nary apparatus. 5

Another purpose of this invention is to render it possible to reduce the thickness of the spiral metal sheets, without impairing the function of the apparatus and without reducing its resist- I ance to shocks and strains. For the heat transmission, it is desirable to reduce the thickness of the sheet metal as much as possible, but heretofore such reduction could not be carried very far without diminishing the resistance of the apparatus, In such spiral heat exchangers it is absolutely necessary, that the metal sheets are not deformed, because otherwise the function of the apparatus will be seriously impaired and the resistance to the flow will increase to values too high for practical operation, rendering the drop of pressure in the apparatus exceeding high.

It was; also proposed to use distance pieces welded to the metal sheets, but the mounting of such pieces, being several thousand in big ap paratus, implies a, great cost and because the welding requires a certain minimum thickness of the metal sheet, the thickness of the metal sheets could not heretofore be reduced as much as desired. The welded spots or seams are also liable 40 to be more easily attacked by corrosion.

Some embodiments of the invention are'illustrated in the annexed drawing.

Fig. 1 is across section through an apparatus in accordance with this invention, taken on the 5 line I-I in Fig; 2. v

Fig. 2 shows an axial section on the line II -II in Fig. 1.

Figs. 3. and 4 show details of axial sections through otherembodiments, in which both of the spiral metal sheets are corrugated.

Referring now to Figs. 1 and 2 of the drawing, the spiral heat exchanger has two spiral metal sheets I and 2, of which the sheet I is smooth, while the sheet 2 is corrugated in such manner that the corrugations extend in the peripheral direction of the spiral, i. e. their longitudinal direction is at right angles to the axis of the spiral. The cold medium is supplied through the pipe 3 and is drawn oil through the pipe 4 after having passed through the spiral channel 8. Analogously, the hot medium enters through the pipe 5, flows through the channel I and is drawn off through the pipe 6.

In the axial direction the channels I and dare closed by strips 9 in well-known manner, for instance, in accordance with U. S. Patents No. 2,011,201 or 1,930,879.

It is evident that the metal sheet 2 is rendered more rigid and'resistive to shocks and pressure as a result of the corrugation, while the spiral flow in the peripheral direction is entirely unrestricted. For this reason, the efliciency of .the

heat transmission is very high.

Fig. 3 shows an embodiment in which the two metal sheets are both corrugated, their corrugations being displaced somewhat in relation to each other. It is easily seen from the figure that the surface of heat transmission per unit of volume is increased in this apparatus, as comstrains are very must increased, without'any increase in the weight of the apparatus, or theapparatusmay be builtof thinner sheet metal,

while still retaining suflicient strength.

By the term corrugated" as used herein, I mean 'a surface having alternate ridges and grooves without limitation to their particular shape. While I have shown and described several more or less specific embodiments of my inveninvention is not to be limited thereby but is to be determined by the appended claims viewed in the light of the prior art.

What I claim is: j 1. In a heat exchanger for indirect heat transmission between fluids, substantially parallel spiral walls-oi sheet metal forming therebetween spiral channels for flow oi the fluids in spiral paths, at least one of said spiral walls being corrugated, the corrugations extending substantially parallel to the direction of flow, the crests of the corrugations abutting along substantially their entire length against the adjacent walls on both sides of said corrugated walls so that all said walls abut directly against each other.

2. In a heat exchanger for indirect heat transmission between fluids, substantially parallel.

spiral walls of sheet metal forming therebetween spiral channels for flow of the fluids in spiral paths, said spiral walls being corrugated, the corrugations extending substantially parallel to the direction or flow, all the corrugations being substantially uniform in shape and abutting against each other on both sides substantially along the entire length of their crests so that all said walls abut directly against each other.

s,ise,o8o

'tion, it is to be understood that the scope of my 3. In a heat exchanger for indirect heat trans mission between fluids, in combination, two substantially parallel spiral walls or sheet metal forming therebetween spiral channels for flow of the fluids in spiral paths, one of said spiral walls being substantially smooth and the other being corrugated, the corrugations extending substantially parallel to the direction 'of flow and the crests of said corrugations abutting on both sides against adjacent turns. of said smooth wall.

- 4. In a heat exchanger for indirect heat transmission between fluids, substantially parallel spiral walls of sheet metal forming therebetween spiral channels, for heat exchanging fluids to pass windings of said metal sheets on both sides abut directly against adjacent windings.

CURT FREDRIK ROSENBLAD. 

